Comcast throttles BitTorrent users

It looks like Comcast, America's biggest cable network, has put the squeeze on BitTorrent users.

On Friday, the widely-read BitTorrent blog TorrentFreak reported that many Comcast users were unable to "seed" their BitTorrent downloads, which severely slows the exchange of music and video over the popular P2P protocol. Comcast has denied any-wrongdoing, but hundreds of BitTorrent mavens continue to complain.

"Over the past weeks more and more Comcast users started to notice that their BitTorrent transfers were cut off," wrote Ernesto, the mononym behind TorrentFreak. "Most users report a significant decrease in download speeds, and even worse, they are unable to seed their downloads. A nightmare for people who want to keep up a positive ratio at private trackers and for the speed of BitTorrent transfers in general."

According to Ernesto, ISPs have been throttling BitTorrent traffic for "almost two years," but he says that Comcast has taken the practice a step further with its clampdown on seeding. In seeding a BitTorrent file they've just downloaded, users are - in essence - offering it up to others on the network. If you prevent seeding, you slow down the entire BitTorrent process. Plus, you make it more difficult for users to upload as much BitTorrent data as they're downloading - which could get them kicked off private BitTorrent "trackers," the servers that coordinate file swaps.

Comcast assured us that it was not doing what Ernesto claims it's doing. Under its current network policy, according to a company spokesman, the company would never block BitTorrent traffic - or traffic related to any other application. The only thing the company would admit to was making polite phone calls to customers guilty of extending some unspecified bandwidth threshold.

"Customers who are notified of excessive use typically and repeatedly consume exponentially more bandwidth than an average residential user, which would include, for example, the equivalent of sending 256,000 photos a month, or sending 13 million emails every month (or 18,000 emails every hour, every day, all month)," the company said. "In these rare instances, Comcast’s policy is to pro-actively contact the customer via phone to work with them and address the issue or help them select a more appropriate commercial-grade Comcast product."

Nonetheless, a new post from Ernesto says that hundreds of his readers have complained about seeding issues on Comcast. "The problems are still happening as we speak," he told The Reg. "There seem to be regional differences, though. Not everyone is affected."

Ernesto speculates that Comcast is using Sandvine broadband traffic management equipment to prevent seeding, and according to one TorrentFreak reader, two Comcast tech employees have admitted to adopting the technology- though they wouldn't comment on the BitTorrent issue. ®